High-frequency (HF) power converters such as battery chargers are prone to exposure to high-voltage transients. Some of the most extreme voltage transients are present during initial power-up of the charger, particularly when the charger is supplied from a power source having a relatively high line inductance. These voltage transients can often exceed the maximum voltage ratings of power switching devices of the charger, such as insulated gate bipolar transistors (IGBTs) and metal oxide semiconductor field effect transistors (MOSFETs). Exceeding the voltage ratings of these devices can damage them, and also other components of the battery charger. The typical solution to avoid such damage is to either add a transformer or an electromagnetic interference (EMI) filter in-line with the charger's power circuit. While both of these solutions aid to reduce the magnitude of voltage transients, they do not provide a solution for all transient and over-voltage conditions. Metal oxide varistors (MOVs) are also commonly employed to suppress voltage transients. However, MOVs typically do not have accurate enough voltage ratings to reliably protect the aforementioned switching devices during voltage transient conditions. There remains a need to more effectively protect power converters from transient voltages, as well as other over-voltage conditions.